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Corporate Information

 
Press Release (May 07,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, May 7)

*Updates are underlined 
All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down. 
Unit 1 (Shut down) 
-Explosive sound and white smoke were confirmed after the big quake 
 occurred at 3:36 pm on March 12. It was assumed to be hydrogen explosion.
-At approximately 2:30 am on March 23, seawater injection to the nuclear 
 reactor through the feed water system was initiated.
-From 3:37 pm on March 25, we started injecting freshwater and are now 
 injecting fresh water by a motor driven pump powered by the off-site 
 transmission line. From on April 27, we have increased the amount of 
 injecting freshwater from approximately 6 m3/h to approximately 14 m3/h. 
 At 10:14 am on April 29, we put the amount of injecting freshwater back 
 to approximately 6 m3/h.
-As it is suspected that hydrogen gas is accumulated inside reactor 
 containment vessel, we commenced the valve opening operation concerning 
 injection of nitrogen gas into the reactor container vessel at 10:30 pm 
 April 6th and commenced injection at 1:31am April 7.
-At 10:01 am on May 6th, in order to make nuclear reactor flooded to the 
 top of Fuel range, we have increased the amount of injecting freshwater 
 from approximately 6 m3/h to approximately 8 m3/h. 
Unit 2 (Shut down) 
-At approximately 6:00 am on March 15, an abnormal noise began emanating 
 from nearby Pressure Suppression Chamber and the pressure within the 
 chamber decreased. 
-From 10:10 am on March 26, we started injecting freshwater to the reactor 
 and are now injecting fresh water by a motor driven pump powered by the 
 off-site transmission line. 
Unit 3 (Shut down) 
-Explosive sound and white smoke were confirmed at approximately 11:01am 
 on March 14. It was assumed to be hydrogen explosion.
-From 6:02 pm on March 25, we started injecting fresh water to the reactor 
 and are now injecting fresh water by a motor driven pump powered by the 
 off-site transmission line. 
Unit 4 (Outage due to regular inspection) 
-At approximately 6:00 am on March 15, we confirmed the explosive sound 
 and the sustained damage around the 5th floor rooftop area of the Nuclear 
 Reactor Building.
-At this moment, we do not consider any reactor coolant leakage inside the 
 reactor happened. 
Unit 5 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 5:00 am on March 19, we started the Residual Heat Removal System Pump 
 (C) in order to cool the spent fuel pool.
-At 2:30 pm on March 20, the reactor achieved reactor cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 reactor happened. 
Unit 6 (Outage due to regular inspection) 
-Sufficient level of reactor coolant to ensure safety is maintained.
-At 10:14 pm on March 19, we started the Residual Heat Removal System Pump 
 (B) of Unit 6 in order to cool the spent fuel pool.
-At 7:27 pm on March 20, the reactor achieved reactor cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 reactor happened. 
Operation for cooling the spent fuel pools 
-From 2:05 pm on May 7th, we started water spay to Unit 4 by the concrete 
 pumping vehicle. 
-We will continuously conduct further water spray depending on the 
 conditions of spent fuel pools, if needed. 
Others 
-The transfer of high level radioactive wastewater in Unit 2 to the 
 Centralized Radiation Waste Treatment Facility was temporarily suspended 
 at 9:22am on May 7th, due to the construction of injection piping 
 (reactor feeding water system) to reactor of unit3.
-The transfer of accumulated water in Unit 6 turbine building to a 
 temporary tank was conducted from 2:00 pm to 5:00 pm on May 3.
-From March 27, transfer of accumulated water in Unit 5 turbine building 
 to a condenser has been conducted, and water with the amount of 
 approximately 600m3 has been transferred from March 27 to May 2.
-From May 2, we have started work relating to the set up of exhausters, in 
 order to improve the working environment inside the reactor building of 
 Unit 1. At 4:36 pm on May 5th, all of exhausters (6 units) were started 
 to operation. 
-The transfer of accumulated water in Unit6 turbine building to a 
 temporary tank was conducted from 10:00am to 3:00pm on May 7th. 
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station. 
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